Well whenever im in drive and im just braking i hear like a popping noise like some one is hitting something with a hammer. It only happens when in drive and while im braking I noticed when it makes that noise my idle drops. What could that be ? It just started happening like a week ago and its getting really annoying. The only thing i have done to my car recently is a custom enterprise y pipe.

 

hmm... It didn't do it before you y pipe? Is it a drastic drop, or a popping while your RPMs normally drops to idle.

 

Check all of your Y-pipe hangers as well as those on the cat.

 

Since your RPM is dropping and you hear the poping sound, it sounds like a backfire. I am not sure how it would have been caused by the y-pipe, but the pop sounds like teh explosion and the rmp drop sounds like it is because teh blast is no longer sealed and not all the energy is confined so it looses power.

 

when it idles it just drops down randomly and it goes POP actually its more like a click as if i was changing the transmission gear. I notice the idle slightly drops - 100 rpm

 

It doesn't click at all when you accelerate?

 

nope only when im braking

 

that be it, check you timing. A lot of the time the motion of the engine during acceleration can tighten things up. But when braking your engine is dropping power quick, so your timing is probably off somehow.

 

Before you start taking shyt apart, where is the sound coming from? Do you feel it on the brake pedal? You may have two seperate problems. Last week, I had a similar sound coming from the front of the car when I applied the brake. It turned out to be the brake pads moving around in the caliper. He spread some blue crap behind each pad and the sound went away.

 

i dont think it would be my timing the engine only has 40k on it. Im not quite sure where its coming from the sound but i think its some where in the middle of the car. I have to do some more investigating. But if its serious i am notputting any more money into this car. If it has to do with the timing cover im crashing the car into a wall. Please do not tell me this is a serious problem. THe car overall runs great.

 

Have you checked for any hidden codes? Even codes such as O2 sensors are "hidden" (no CEL) until the ECU gets a constant signal for an 'X' amount of time before it triggers a CEL light.

 

not recently but ill check wednesday.